Summary

The following factors will influence the snowmaking:

Wetbulb temperatureWetbulb temperature is calculated from air temperature and relative humidity.The wetbulb temperature is directly related to the snowproduction efficiency.
Throw distance/Drop height For fan guns we use the teminology «throw distance», while for snow lances we say «drop height»  The longer throw disatance/drop height, the more time the water droplets have to freeze to and become snow  
Water capacityThe water capacity for the fan gun is dependant on the water pressure and the size of the nozzle/number of nozzles that are open.The higher the water pressure , the more water is pushed through the nozzles and the better the atomization of the  water is!
Water temperature  The water temperature is dependent on its origin and method of storage.    The higher the water temperature is the longer it takes for the water to freeze after it is sprayed out into the air. 
WindIf the wind increases or turns, the snowmaker must carefully watch to prevent the units from icing down.  Changing wind condition and headwind can lead to icing and damaged equipment, as well as possible damaged infrastructure such as lifts, light towers etc.    
LossLoss of snow volume may be due to:
– Evaporation
– Melting/ablation
– Too much water
– Wind drift 
Except from ablation/melting due to temperature, sun or wind, it is the staff’s responsibility to prevent that the conditions worsen due to these factors.
Excerpt from table by Norwegian Ski Federation